Herseth Sandlin said an outbreak would be “devastating” to livestock producers and rural economies in her state.

“We simply cannot take chances when we’re talking about the economically devastating impact that foot-and-mouth disease could have on a family ranch,” said Cubin.

The USDA rule would allow fresh and frozen meat from the southern Patagonia region of Argentina. The agency argues that the region has been FMD-free for decades and the Argentine government has taken the necessary precautions to prevent another outbreak.

The rule is still pending, according to Karen Eggert, media coordinator for the USDA’s Animal and Plant Health Inspection Service. Eggert could not comment on any proposed legislation regarding the rule.

USDA now only allows beef from Argentina that is cooked. Cooking the meat at a certain temperature kills any trace of FMD.

Cattle groups worry that if fresh and frozen meat were allowed to enter the U.S., some might fall into the U.S. feed supply, infecting U.S. herds. They also say the disease could go airborne and infect cattle.

The disease attacks livestock, such as sheep and cattle, producing lesions in their mouths and hooves. FMD, highly contagious, can wipe out entire herds.

Lobbyists for the cattle industry insist they’re not trying to keep out competition from Argentina, and that there’s too great a risk of foot-and-mouth disease to allow any beef from that country, regardless of its region of origin, to enter the U.S.

“There is no worry about import impact. The real threat is disease and what it could do to our rural economy,” said Leo McDonnell, director emeritus of the United States Cattlemen’s Association (USCA).

Still, studies suggest prices for U.S. producers would decline if the ban on Argentine meat were lifted.

About 13.2 million pounds of sheep meat per year would arrive in the United States under the new rule, according to estimates provided by the Argentine government to the USDA. Consequently, prices for U.S. lamb and mutton could decline about 10 cents per pound — potentially an annual $17.7 million loss for American sheep ranchers.

The beef industry could also be affected, given the fact that Argentina is a powerhouse beef exporter, although in recent years its government has sometimes intervened to depress its own exports in order to lower domestic prices. Even exporting only cooked beef, it is the sixth-largest exporter of beef to the U.S., according to statistics from USDA.

The U.S. beef industry was valued at $36.1 billion by USDA last year. It produced more than 26.4 billion pounds of meat in 2007. It’s also the top beef exporter in the world, although it has been pained in recent years by restrictions in Japan, South Korea and other countries worried about cases of mad-cow disease in North America.

USCA is a member of the American Task Force Argentina (ATFA), a coalition of about 40 organizations that have been affected by Argentina’s debt default in 2001. Those groups have lobbied the U.S. to pressure Argentina to repay debts wiped out through its default.

Robert Raben, AFTA’s executive director, said the default also boosted Argentina’s agricultural exports by lowering its currency, which dropped prices for several of the country’s farm goods.

“It certainly had internal ramifications, but it helped the farm sector. It was an export promotion tool,” Raben said.

Legislation banning meat imports from Argentina has also found support from other powerful farm lobbies. For example, the National Farmers Union (NFU) has written to Johnson in support of his bill.

“The ban proposed in your legislation is necessary in order to prevent jeopardizing our own efforts to eradicate livestock diseases, and thereby protecting the food supply,” wrote Tom Buis, NFU’s president, in a July 10 letter to the South Dakota Democrat.

Enzi and Johnson’s legislation has already attracted nine other co-sponsors. More House members are expected to sign on to their chamber’s version of the bill.